Using gelatin to bulk up "muscles-on-a-chip"

The team was able to grow myotubes in a geltin hydrogel (Credit: USC/A Bettadapur/G Suh/E Wang/H Huber/A Viscio/ M McCain)

Growing muscle for lab-based testing is a tough process, and previous attempts to do so – making use of plastic scaffolds – have failed to produce fully-formed muscle fibers. Now, a team from the University of Southern California (USC) has taken a different approach, using gelatin and a water-logged gel, or "hydrogel," as a scaffold.

This new research is the latest in a series of "on-a-chip" efforts that have seen scientists create lab-based versions of everything from lungs to working models of heart disease. The idea is to produce systems in the lab that accurately simulate organs and other tissue, allowing researchers to conduct studies and develop new medicines with zero risk to patient health.

During embryonic development, muscles form around the skeleton when cells called myoblasts join together to create fibers called myotubes. Researchers have tried to recreate the process in the lab, attempting to grow mouse myotubes on tiny plastic structures, but the fibers simply won't grip and hold onto the material, slipping away after just one week, and failing to grow as desired.

To get around the problem, the USC researchers decided to try growing the fibers on a different kind of scaffold, using a hydrogel made from gelatin – a derivative of naturally occurring muscle protein, collagen – instead of plastic.

Though the gel is largely made up of water, its mechanical properties are more similar to those of the natural growth environment; as it is a natural biomaterial, cells are more likely to stick to it and grow as normal.

The material appears to have performed well in the USC study. After three weeks, the researchers observed that the mouse myotubes were firmly attached to the hydrogel scaffold, growing wider, longer, and generally developing as hoped.

While further study is certainly required, the researchers believe that human myotubes could be grown using the same method, on gelatin chips. Such "muscles-on-a-chip" could then be used to study muscle development, and be used as a platform for drug testing.

"By creating an inexpensive and accessible platform for studying skeletal muscle in the laboratory, we hope to enable research that will usher in new treatments for these patients," said USC's assistant professor, and study lead, Megan McCain.